1998-2001 Mercury-MerCruiser GM V6 262 CID 4.3L Marine Engines Service Manual Number 25

SERVICE MANUAL Number 25

MARINE ENGINES
GM V-6 262 CID (4.3L)

MerCruiser #25 GM V-690-861328–1262 CID (4.3L)

Notice

Throughout this publication, “Dangers,” “Warnings” and “Cautions” (accompanied by the International HAZARD Symbol ) are used to alert the mechanic to special instructions concerning a particular service or operation that may be hazardous if performed incorrectly or carelessly. OBSERVE THEM CAREFULLY!

These “Safety Alerts” alone cannot eliminate the hazards that they signal. Strict compliance to these special instructions when performing the service, plus “Common Sense” operation, are major accident prevention measures.

Notice to Users of This Manual

This service manual has been written and published by the Service Department of Mercury Marine to aid our dealers’ mechanics and company service personnel when servicing the products described herein.

It is assumed that these personnel are familiar with the servicing procedures of these products, or like or similar products manufactured and marketed by Mercury Marine, that they have been trained in the recommended servicing procedures of these products which includes the use of mechanics’ common hand tools and the special Mercury Marine or recommended tools from other suppliers.

We could not possibly know of and advise the service trade of all conceivable procedures by which a service might be performed and of the possible hazards and/or results of each method. We have not undertaken any such wide evaluation. Therefore, anyone who uses a service procedure and/or tool, which is not recommended by the manufacturer, first must completely satisfy himself that neither his nor the products safety will be endangered by the service procedure selected.

All information, illustrations and specifications contained in this manual are based on the latest product information available at the time of publication. As required, revisions to this manual will be sent to all dealers contracted by us to sell and/or service these products.

It should be kept in mind, while working on the product, that the electrical system and ignition system are capable of violent and damaging short circuits or severe electrical shocks. When performing any work where electrical terminals could possibly be grounded or touched by the mechanic, the battery cables should be disconnected at the battery.

Any time the intake or exhaust openings are exposed during service they should be covered to protect against accidental entrance of foreign material which could enter the cylinders and cause extensive internal damage when the engine is started.

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It is important to note, during any maintenance procedure replacement fasteners must have the same measurements and strength as those removed. Numbers on the heads of the metric bolts and on the surfaces of metric nuts indicate their strength. American bolts use radial lines for this purpose, while most American nuts do not have strength markings. Mismatched or incorrect fasteners can result in damage or malfunction, or possibly personal injury. Therefore, fasteners removed should be saved for reuse in the same locations whenever possible. Where the fasteners are not satisfactory for re-use, care should be taken to select a replacement that matches the original.

We reserve the right to make changes to this manual without prior notification. Refer to dealer service bulletins for other pertinent information concerning the products described in this manual.
Engine Mechanical Components

Many of the engine mechanical components are designed for marine applications. Unlike automotive engines, marine engines are subjected to extended periods of heavy load and wide-open-throttle operation and, therefore, require heavy-duty components. Special marine engine parts have design and manufacturing specifications which are required to provide long life and dependable performance. Marine engine parts also must be able to resist the corrosive action of salt or brackish water that will rust or corrode standard automotive parts within a short period of time.

Failure to use recommended Quicksilver service replacement parts can result in poor engine performance and/or durability, rapid corrosion of parts subjected to salt water and possibly complete failure of the engine.

Use of parts other than recommended service replacement parts, will void the warranty on those parts which are damaged as a result of the use of other than recommended replacement parts.

Replacement Parts

WARNINGElectrical, ignition and fuel system components on MerCruiser Engines and Sterndrives are designed and manufactured to comply with U.S. Coast Guard Rules and Regulations to minimize risks of fire or explosion.
Use of replacement electrical, ignition or fuel system components, which do not comply to these rules and regulations, could result in a fire or explosion hazard and should be avoided.
When servicing the electrical, ignition and fuel systems, it is extremely important that all components are properly installed and tightened. If not, any electrical or ignition component opening would permit sparks to ignite fuel vapors from fuel system leaks, if they existed.

Page ii 90-861328–1 NOVEMBER 1999
Service Manual Outline

Section 1 – Important Information
A – General Information
B – Maintenance
C – Troubleshooting

Section 2 – Removal and Installation
A – MCM Models

Section 3 – Engine
A – 262 CID / 4.3L Engines
Section 4 – Electrical Systems
A – Starting System
B – Ignition System
C – Charging System
D – Instrumentation
E – Wiring Diagrams
Section 5 – Fuel Systems
A – Fuel Delivery System For Carbureted Engines B – Mercarb 2 Barrel Carburetor
C – Weber 4 Barrel Carburetor
D – SAV1 Emission Fuel System With Weber Carburetor E – Fuel Delivery System For Electronic Fuel Injection F – Fuel Injection Descriptions And System Operation G – Fuel Injection Disassembly And Reassembly H – Fuel Injection System Troubleshooting
I – Diagnostics
Section 6 – Cooling System
A – Seawater Cooled Models
B – Closed Cooled Models
Section 7 – Exhaust System
A – General
B – Manifolds, Elbows and Risers
C – Collectors
Section 8 – Drives
A – Drive Shaft Models

Section 9 – Power Steering System
A – Pump and Related Components
Important Information 1
Removal and Installation 2
Engine 3
Electrical Systems 4
Fuel Systems 5
Cooling System 6
Exhaust System 7
Drives 8
Power Steering System 9

90-861328–1 NOVEMBER 1999 Page iii
Table of Contents IMPORTANT INFORMATION
Section 1A – General Information